Portable dynamometer brake



Aug. 7, 1951 B. BRITT PORTABLE DYNAMOMETER BRAKE 4 Sheets-Sheet 1 FiledNov. 29, 1944 FIGI.

INVENTOR. BRYANT L.BRITT ATTORNEY.

1951 B. L. BRITT 2,563,153

PORTABLE DYNAMOMETER BRAKE Filed Nov. 29, 1944 4 Sheets-Sheet 2 INVENTORB A LBRITT BY ATIDRNEY.

FIG14.

Aug. 7, 1951 B. L. BRITT PORTABLE DYNAMOMETER BRAKE 4 Sheets-Sheet 5Filed Nov. 29, 1944 INVENTOR. v T L BRITT ATTORNEY.

l atented Aug. 7, 1951 I UNIT Eo- SJ'IWEES PORTABLEDYNAMOMETERBRAKEE'Ecorporati'on of D'elaware This mventidn=re1ate to dynarriometer andinitsmOre-SpecifiiFaSpeCtSis directed to' a pdiftbi dynamometer" whichreadilwemployablto; test "the horsepower-output of motors rangin'gi;

power' cutout? One-of the objects of theinventibrris td"pro"-f vide-"aportable clyriamoi'neterthat mayheieadily attachedtoand detachdfr'omjan"'eiectric motor" test stand:

Another. object-tortheinventioniis to'f rovi e' a" dynamometer" brakewhich mayjbe' readily;

arran ing" the latter iontaizstatioriary"teststand. 15

A 'flirth'erfobj't of tn'ex riventidnis ito rovide; ai portable P i'dr-iiz'brake -whi'chlis'. a art o f ."a-'port-. able: motorts'fiiiigfiequiliment that is readily. attachable to. aflniotorjrestingeon anflordinar yfl Another. and. stili f'fiirthr object of theyinven-r tion is. to pro'dlioe a.-;portab1 e',dynamometerrprovided'tvithianpliiralitypofiadjiustrnenteithatenable; itItolbe easilii centeredwithlrespeettortheaema ture shaft 10f themotorundii tstl i I 25 A Lstill" flirth'eri pbie'et Q of tl ieyinventienw-isto provide a 1 portable-2; Pier-131; brake; fori portable? motortestinggi equipment-in Wh -Ghv' the brake; shoee arehydrauliealiyapplied :toiawbrakesdrum q readilii rattaehableotw and detaehab1-from:'-the2 30 str'tietiire' comirigiwitf-iiz'a -the spi-r it and soopethrof are deemed trrh inoliidd herei-n a' In the -drawiiisc I Fifire-"-1 is a lan viewof -tiie portable mome'terf Figure2 is' a=side-e1evationa1 view thereof-i Figure 3 is-'a schematichydrauli'layout bfti'i essentialapparatli" ei n'plliyed in theporta'Jifl dynamometer: U Figure 4 *is "afront elevatiiinalyi-ewthereofFigure 5 ie a View taken substantially-along the line5 5of'fi'g irefl'j4 Figure 6 isa si'defelvati'driai 'vi'e'w offamodifiedform"'oftheinventioniand l V Figure? is afronfi'eievatioiialjyiewi thereof? Commercial rajc tibe'for nieas'uriiigfthe"h0r;e=' poweroutput of fffraidtionalj and larger'f sized; motors has "in the pastbeen'fgenerauyiperformed? on stationary tes'tiiigli dvio's whihincorporate 1' a Pr'onib'rake Ofa mOtOf generator sefl' the? motor undertest b'inggthbnejdrivifiggthe tsti'fi generator. This niethodTof"testing. .has" always; required the .moving and Settingup Qfth. motoror engine under test in the -partieular apparatnse provided thereforand. vneceisitated the handlingof the motor 'inder te stat-least twiceto perform one; test. has;-- involveci. a considerable; amount of laborandilost motion and requires the employment ofvarious types ofblocking-in orden to bring the shaftofthe-prime mover ande-tlme testbrake or the ltesting pgeneratoriintovalignea menta- Anotherdisadvantage to beconsiderediim the prior art is the fact that 'testgenerator-seen? brakes set, up 5 onlstationary dynamometers shave-3 been4 too large for the smallertype Off-IIIOGOFffiHdJE if one is designedforrfai -small motor; it wasfi-icutitireadily adaptabletoxone of aalarger 'sizez The? objections to commeroiahpractice? now :pur sue' areovercome-.=in -'-th instant' distilosures whie provide et er-table dvice' tIiiatiS mQVabIe up w the motorinstead ofimoviiig th'e m0tor= u1$td and by the siriiple fiefiiiediem: u r m g- :t -e pressures orchanging the si'zef or dimensions "of" the brake unitor" by substituting'a' difireiit brake I assembly I which can" be employedeithera'reiatiyeiy large or acomharativiy sm'afiifmotor. Inthe"eventofiretzsSitY;'mflirisfohtli device provide for aquickndjiiStn'ienFto substi' tute different -brake"-assemb1iesf whennecessary, for theone installedso that the size ofthjbralf will be'proportioned and"'in"keepingfwith tfi 5 motor or engine undrgojiiigtest.The objects and 'adt'lai'itage'sioutlined above are? obtainedin "adev'ic'elset forthfinfthe accompany;

3 ing drawings in which I is a manufacturer's transport stand ordinarilyquite generally found in manufacturing establishments for moving goodsfrom one section or department of a factory to another. Numeral 2 refersto a similar stand on which the brake assembly subsequently described isarranged. The transport stand I is intended to support a motor or engineunder test and a vertically adjustable supporting base 3 is providedthereon. The provision of the supporting base is optional on the part ofan operator and, when used, provides an additional adjustment toincrease the flexibility of the testing device. The supporting basecomprises a pair of frame elements 4, 4 extending substantially parallelto the axis of the motor 5 under test and it is provided with a pair oftransverse or crossmembers 6, 6 on which the base I of motor 5 issecured by means of a plurality of screw elements 8, 8 threaded intomembers 6, 6. Arranged in the members 4, 4 are adjusting screws 9 whichare threaded therein and into nuts 9a. welded to the members 4, 4. Thelower ends of the screws may be rotatably received in a plurality ofbrackets I 0, ID in order to secure the same to the transport member Ito prevent relativemovement of the base 3 with respect to the transportelement I. The adjusting screws 9, 9 are also used for leveling themotor 5 with respect to the supporting surface as well as providing fora vertical adjustment.

The transport stand 2 has a pair of cars II, I I thereon which cooperatewith similar ear elements I2, I2 on transport standv I, each of which isprovided with suitable axially alignable apertures in which boltelements I3, I3 are inserted in order that the two transports may belocked together during the period of test. The primary object ofproviding the ear and bolt' elements on the transports is to prevent anypossible whipping or rotation of one of the transports with respect tothe other and thereby maintain the same in a more stable condition:

The transport 2 has supported thereon a frame member I4 supporting thebrake assembly which comprises a pair of channel or other appropriatelyshaped bar members I5, -I5 having a plurality of adjusting screws-I6, isin each, the ad justing screws being preferably-limited to two in eachbar member. Each of these adjusting screws is threadably received in theappropriate apertures formed in members I5, I5 provided with nutelements I1, I! also threaded to the screws. The nutelements arepreferably welded or otherwise secured to the channel members to preventpossible relative movement thereof with I respect to the bar members I5,I5. In order to maintain the adjusting screws I6, I6 fixed to thetransport 2 to prevent relative movement thereof, it has arrangedthereon a plurality of brackets I8, I8 equal in number to the number ofscrews. The adjusting elements 9, 9 and I6, I6 are so shaped at theirends that they will rotate within the respective brackets I and I8. Thisconstruction prevents the movment of frame I4 with respect to thetransport during any period of test. The frame I4 is operable withoutmountingon transport 2 but its maneuverability is facilitated when somounted.

The frame I4 is further provided with a pair of uprights I9 and 25secured to a transverse member 2|. The members I9, 20 and 2| are securedtogether as a single unit illustrated more particularly in Figure 4which is welded or other' wise secured to members I5, I extending in thesame direction as members 4, 4 previously discussed. Rotatably movablewithin the uprights I9 and is a member 22 functioning as a torque armwhich is secured to the backing plate of a brake assembly. The rotationof arm 22 is materially limited in the frame elements I9, 20 and 2| bymeans of screws 23, 23 in order to aid in stabilizing the structureduring movement from one station to another. It is, therefore, evidentthat the brake assembly supported on arm 2? can be adjusted with respectto the motor by 4 means of screws I5, I6 to align the two and thatscrews 23, 23 limit the rotation of the torque arm 22 to confine same toa substantially horizontal position in addition to the functionpreviously set forth. These screws during periods of idleness clamp thetorque arm against pressure fluid devices subsequently described. Duringoperation'the torque arm must be freely movable in frame members I9 and20 and are withdrawn therefrom a short distance.

Referring now to Figure 5 there is, disclosed a sectional view of thebrake assembly in which the backing plate 25 is shown secured to member22 previously discussed by means of a plurality of screws 26, 26 with areinforcing plate 24 disposed immediately adjacent backing plate 25.Mounted on the backing plate 25 is a pair of brake shoes 21 and 28 whichmay be either pivoted to the backing plate itself o1 pivoted to getheras shown in Figure 8. A pressure fluid motor or brake cylinder 29 islikewise fixed to the backing plate having a pair ofpis'to'ns (notshown) therein operating in the usual manner and engaging the ends ofthe brake shoes to expand the same into engagement with the brake drum30. v The brake drum 3!] has an adapter or connector element 3| securedthereto by means of a pluralityof screws 32, 32 with the adapter elementkeyed to the armature shaft 33 of motor 5 by key 34, the particularconnection being employed because it facilitates quick removal from andattachment to the armature shaft.

The backing plate 25 and its associated structures are journaled on thedrum 30 so as to provide for centering the one upon the other which isaccomplished by integrally associating with the drum an inwardlyextended flange or boss 35 that cooperates with the bearing'pin 36 whichin this instance is secured to member 22 with plate 24 disposed betweenthe bearing pin flange 31 andbacking plate 25. The particular mode ofjournaling, as illustrated, provides the element 35 of the brake drum 30with appropriate counterbores in order to receive anti-friction bearings38 and 39 which may be conventional in character, the inner races of thebearings received on differentially diametered pin 36. The illustrationshows the assembly as having two separate bearing members but it is notnecessarily limited to this particular bearing organization, the onlyessential feature being that it is necessary to provide some means forfreely journaling the drum 30 on the backing plate 25.

Disposed within and secured ,to element '2I at each end thereof arepiston cylinder devices 40.

and 4 I, saiddevices being suitably secured to the ends of member 2|. Itis evident, therefore, that when the brake shoes 21 and 28 are appliedto the brake drum by pressure fluid,the backing plate and its associatedtorque arm will tend to rotate with the brake drum. However, one of theends of torque arm 22 will bein engagement with one or the other of thepistonelements of members 40 or M depending upon the directiono'f'r'otationof motor 5, which will then cause drum 30 and backing plate25 'to rotate relatively assessc to each other. The entire. brakeassembly durin test isrotatable with the motor. armaturerntil therotation: of the backin plate :isstqpped by the torque arm enga n oneoif the-eleme f d vices .40 and 4| wl-iich absorb the to qu d e velopedby the motor '5 as transmi te the eto throu the brakeshees 2 andZiii-con act with drum and then e thr u h backin p ate 2.5 and torque rm2. By p ac nelh xis of rotation of shaft 33 and d um 11a di n e uch asone. fo t from the c n er-or po t of contact or a 2 with the meterdevice wand t it eviden t an p e sure read n n. t a measur n h es ured lred 1. 30 e othe o be is y inde e ces .0. e 4| .will sire a d rectreading o mete -Que de elo d y the mot n e t -and n o i sl therefore,read the'torque .in foot pounds. This is a convenient method ofobtaining the results although the distancebetween the center of axisrotation of the drum and the point of application of elements 22 toeither of the piston cylinder devices 40 or 4| can be read directly onany type of gage providing it is .calibratedin'terms of foot pounds'oftorque as applied to the particular length of torque arm 22.

Pressure fluid may be applied to the brakes from a conventionalcompensating master cylinder 4'2 which is provided with a leadscrew 43having a hand wheel 44 attached thereto. The provision of the hand wheel44 and the lead screw 43 will enable a very fine incremental ordecremental adjustment of the pressures to be applied to the brake shoes21 and 28 by means of brake cylinder or motor 29.

A suitable bracket 45 is provided on a convenient base or may becarried, if so desired, on one of the frame members l5, l5 within'easyview'of the gage to be subsequently described. The compensating mastercylinder 42 has connected thereto a conduit 46 leading to a four-wayfitting 41. Another conduit 48 leads to the brake cylinderor motor 29 tosupply pressure thereto. Arranged in another one of the outlets of thefour way fitting 4! is a conduit 49 having a cut-off valve 50 thereinand the valve 50 is connected to the piston cylinder device 4| by meansof a conduit 5|. The fourth outlet of the four -way fitting 4] has aconduit 52 connected thereto leading to acut-ofi valve 53 and the valveis connected to piston cylinder device4|l by means of a conduit 54. Inorder to determine the pressures existing in the several conduits, thepiston cylinder devices 40 and 4| have conduits 55 and .56,respectlvely, connected thereto which terminate in a three=way orcross-over valve fitting 51. The fitting 51 includes a two-way valvehaving an op! erating handle 51 for directing the flow of fluid fromeither conduit 55 or 56 into conduit 58 while preventing the flow offluid between the other conduit and conduit 58. The common side orfitting 51 has a conduit .58 secured thereto and in the schematicdiagram there is shown a pair of gages 59 and 60 connected to conduit 58by means of conduits 6| and 62, there being a shutofi valve 63 arrangedin conduit 6|. The reason for showing two gages 59 and 60 is that onemay be employed for measuring comparatively high pressures and the otherfor reading comparatively low pressures with valve 63 being closed whencomparatively high pressures are to be measured in order to preventdamage to the meter or gage 60 which is normally intended to measure lowpressures. The conduit organization in Figures 1, 2, 4, and 5 variesslightly from that 'in Figure 3 .for the reason-that the circuit hasbeen p ifi d Fi ure-s but its ope ati 1a piston cylinder devices .40 andill is, employed for any givendirection of rotation, valve :50 ora53.-.:is to lbelclosed depending upon which of-.;the..aforee saidpiston cylinder devices isemployed .As-the pressureon the brake shoes istin'creasedor .decreased, it is obvious that the load will be rm creasedor decreased and, therefore, the pressure to be applied to the pistoncylinder devices-4|] and ill will likewisebe increased or decreasedwhich is in direct proportion to the torque de.-. veloped by; the motor.The gages .59 and .61) are directly associated with the respectivepiston ,cyl-e inder devicesltfl vand 4| and since the torque de-.veloped by the motor willchange-with the load applied thereto, it isevident that the pressures developed :by member-t22 acting against.either one of the piston cylinder devices All and 41 will alter thereading on the meters .or gages 59 and :66 ;to inform the operator ofthe power output of the motor under test. :Shaft 33 in realitysupportsthe brake assembly during op.- eration such that torque developed could:be measuredzdirectly. Screw 23 confines the movement of arms 22 at alltimes.

. A suitalble fixture 64 is secured to the backing plate and connectswith the brake cylindermotor 29in order to connect the conduit 48thereto. The valves 50, 53 and 63 may be conventional in characterwhereby the pressure fluid is directed to either ofthe piston cylinderdevices 40or' 4l.

The piston cylinder devices 40, 4| are employable as a verticaladjusting means for the torque arm 22 and the attachedbrake assemblyafter the loosening :of screws 23, 23. When hand wheel 44 ofcompensating master cylinder 42 is rotated pressure fluid can be forcedinto devices 45, 4 1 when valves 511v and .53 are open. The pressurefluid forced from the compensating master cylinder will move the pistondevices upward, thereby. lifting or vertically adjusting the torque arm22 assembly. This procedure produces a very fi-ne adjustment becausescrew .43 must axially travel a considerable distance in order to movearm 22 vertically an appreciable distance, thereby effecting a muchfiner adjustment than is possible with screws l8, l5 whenever this isnecessary. After the vertical adjustment of the assembly has beencompleted the valves 50 and 53 are closed before the motor is placed ontest. The closing of valves 55 and 53 isolates the measuring sys-'- tornfrom the fluid supply system and thus allows a true reading of thepressure produced in the cylinder 40 or 4| to be indicated by the gage.

It should be evident from the foregoing deor a' dimension oth'er thanone foot I A modification f the "foregoingstructure is set'forth inFigures 6 and '7. This modification is directed to a means for using thecombined torque arm and brake assembly set forth above in a bench-typemechanism particularly adapted for use in testing small or fractionalhorsepower motors. These figures show a bench 65 of the table-typecommonly found in industrial establishments. Secured to one end of thebench is-a pair of. uprights 66having slots 61 and 68 formed therein,one in each upright. These uprights are securable to the bench in anysuitably manner and for practical purposes can be considered a partthereof.

A frame member 69 is constructed similarly to the frame member shown inthe above disclosure which comprises elements I9, 20 and. 2| and isherein shown comprising the vertical-elements l0 and H secured to orintegral with the horizontal element 12.

Bolts 13 and 14 are inserted through slots 61 and 68 in uprights 66 andare intended to normally clamp the frame 69 to said uprights B6. Thetorque arm 15 andits brake assemblylB are identical in construction withthe corresponding element 22, 25, and 30 and its associated shoes 21 and28 and brake cylinder 29 described above. Arranged at each end ofelement 12 are piston cylinder devices H and 18 which may be identicalin construction with piston cylinder devices 40 and 4|. The parts, suchas the compensator, control valves, gages, et cetera, disclosed indetail in Figure 3 and structurally shown in Figures 1, 2, 4 and 5 areidentical with those employed in the modification shown in Figures 6 and7. In view of the fact that small or fractional horsepower motors areeasily handled when arranged on benches similar to 65, it is more 1convenient to move the motor to the testing device than to move thetesting device to the motor as is done in the preferred embodiment ofthe invention.

The rough adjustments of the torque arm 15 and l brake assembl 16 aremade by loosening bolts 13 and I4 and manually bringing the brakeassembly in substantial alignment with the armature shaft of a motor 19that is under test and any finer adjustments which may be necessar tobring the axes of the brake drum l6 and the motor shaft into alignmentare made by actuating the compensator as explained above, therebyeffecting an unusually fine vertical adjustment. By means of the deviceshown in Figures 6 and '7 a rapid testing of motors may be accomplishedand the method of vertical adjustment set forth above employing thepiston cylinder devices 40 and 4! is much more effective for the instantpurpose than adjusting screws 16 which are intended for larger andheavier pieces of equip ment that must be adjusted such as employed inconnection with larger motors.

Because of the simplicity of adjustment and the portability of thedevice it is employable not only as a factory or production testingdevice but may be as easily and readily employed in small motor orgenerator repair shops or in other commercial establishments that wantto obtain a quick test of the power output or the efficiency of themotor without moving it to some distant stationary testing stand.

Having fully described my invention, that which I claim as novel anddesire to protect by Letters Patent of the United States is;

1."In'a-'Prony brake device for'testing' ainotof, a support; means forvertically 'adjusting said support; an upright frame held on saidsupport; a'pair of pressure fluid devices in said frama one disposed ineach end thereof; a brake assembly including a brake drum secured to themotor being-tested, a backingplate, means journaling said drum on saidbacking plate and brake shoes mounted on'said backing plate engageablewith said drum; a torque'arm secured to said backing plate whose endsare normally supported on said pressure fluid devices; means for causingvarying pressure to be applied by said brake shoes to said drum,said'assembl when employed during a testing operation supported on theshaft of said motor under test such that said pressure fluid deviceswill absorb the torque developed; and gage means associated with saidpressure fluid devices for directly reading the developed torque;

2. In a portable motor testing device, means for supporting a brakeassembly, said assembly including a brake drum securable to a motor'tobe tested,'a backing plate, a torque-arm secured to said backing plate,and brake shoes on said backing plate; a pair'of pressure fluid devicesin said means, one device disposed on one side of said drum and theother device disposed on the opposite side of said drum, said torque armselectively engageable. with each :of said devices; means for applyingsaid brake shoes to said drum means for measuring the torque produced bythe motor under test; and means for vertically adjusting said brakeassembly which includes screw elements in said first mentioned means formaking major adjustments and said pair of pressure fluid devices actingthrough said torque arm vertically adjusting said brake assembly forfine. adjustments. I Y

3. In a motor testing device, a brake assembly comprising a brake drum,a backing plate, brake shoes on said backing plate, means journalingsaid drum on said backing plate and a brakecylinder for urging saidshoes into engagement with said drum, said drum securable to a motorltobe tested; a frame in which said brake assembly is received; a torquearm fixed to said backing plate; a pressurezfiuid device arranged oneach side of said frame adapted to be selectively engaged by said torquearm depending upon the direction of rotation of the motor to be tested;gage means associated with said devices for measuring the torque appliedto each of said devices; means forapplying pressure fluid to said brakecylinder for loading the motor to be tested; and conduit meansassociating said devices with said last mentioned means for verticallyadjusting said brake assembly for aligning it with the motor to betested.

4. In a testing device for amotor having an extended armature shaft, abrake assemblyj means for supporting said brake assembly; pressure fluidoperated means on said supporting means for vertically adjusting saidbrake assembly with respect to said motor in order to align saidassembly with respectto the extended motor shaft, said brake assemblyincluding a drum, a backing plate and a brake shoe thereon; a brakecylinder for applying said brake shoe to said drum; means for measuringthe torque developed by the motor which includes a torque arm securedto'said backing plate engageable with said pres sure fluid operatedmeans; a gage associated with said pressure fluid means; and means forapplying pressure fluid to said brake cylinderforiine.

9 creasing the load on said drum and motor in deflnite increments.

5. In a motor testing device, a brake assembly comprising a brake drum,a backing plate, brake shoe means on said backing plate, means forjournaling said drum on said backing plate, and a brake cylinder formoving said shoe means into engagement with said drum, said drumsecurable to the motor to be tested; a frame in which said brakeassembly is received; a torque arm fixed to said backing plate; apressure fluid device arranged on each side of said frame adapted to beselectively engaged by said torque arm, depending upon the direction ofrotation of the motor being tested; a single gage means assosiated withsaid pressure fluid devices for measuring the torque applied to each ofsaid devices; means for applying pressure fluid to said brake cylinderfor loading the motor being tested; conduit means associating saiddevices with said last mentioned means for enabling said brake assemblyto be vertically adjusted for alignment with the motor being tested; andvalve means between said single gage and said pressure fluid devices forcausing said gage to indicate the pressure exerted by said torque arm oneither of said pressure fluid devices while sealing off the other ofsaid pressure fluid devices.

6. In a motor device; a support; means for vertically adjusting saidsupport with respect to a motor to be tested; a brake assembly; a frameon said support, said brake assembly normally supported in said frame,said brake assembly including a brake drum securable to the motor to betested; a backing plate and brake shoes on said backing plate, said drumjournaled on said backing plate; a torque arm secured to said backingplate whose ends are received in said frame on diametrically oppositesides of said assembly; pressure fluid means in said frame engageable bythe ends of said torque arm; means for applying said brake shoes to saiddrum; means associated with said pressure fluid means for measuring theforce applied thereto by said 10 torque arm; and means for normallyholding said torque arm in said frame and adjustable for allowing saidtorque arm to rotate relatively to said frame a limited amount duringoperation of the testing device.

7. In a portable motor testing device; means for supporting a motorbeing tested; means for vertically adjusting said motor with respect tosaid support; a brake assembly; means for supporting said brakeassembly; means for connecting said motor supporting means and saidbrake assembly supporting means, said brake assembly including a drumsecurable to the shaft of said motor; a backing plate having a brakeshoe thereon engageable with said drum; a torque arm secured to saidbacking plate; fluid pressure operated means for measuring the torquedeveloped by said motor delivered to said fluid pressure operated meansfor measuring through said torque arm; means for vertically adjustingsaid brake assembly which includes screw devices for making majoradjustments and said fluid pressure operated means for making minoradjustments, said fluid pressure operated means engaging said torque armemployable as vertical adjusting means; and means for applying saidbrake shoe to said drum in definite increments of brake shoe pressure.

- BRYANT L. BRITT.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 1,418,655 Klemmer June 6, 21,445,923 Wilder Feb. 20, 1923 1,452,905 Beehler Apr. 24, 1923 1,642,095Tracy Sept. 13, 1927 1,777,423 Zeder Oct. 7, 1930 2,321,652 Carliss June15, 1943 2,372,420 Garrett Mar. 27, 1945 2,405,060 Scofield July 30,1946

